SI単位 - 長さ | NIST

SI Units – Length | NIST Skip to main content Official websites use .gov A .gov website belongs to an official government organization in the United States. Secure .gov websites use HTTPS A lock ( Lock A locked padlock ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites. https://www.nist.gov/pml/owm/si-units-length Physical Measurement Laboratory Office of Weights and Measures SI Units – Length Share Facebook Linkedin X.com Email Credit: NIST Resources for Students and Teachers | How do I get a metric ruler? | When did the metric redefinition of the inch occur? | League of SI Superheroes – Meter Man The meter (m) is defined by taking the fixed numerical value of the speed of light in vacuum c to be 299,792,458 when expressed in the unit m s −1 , where the second is defined in terms of ∆ν Cs . The meter was once defined by a physical artifact - two marks inscribed on a platinum-iridium bar, like these from the NIST Museum . From the meter, several other units of measure are derived such as the: unit of speed is the meter per second (m/s). The speed of light in vacuum is 299 792 458 meters per second. unit of acceleration is the meter per second per second (m/s 2 ). unit of area is the square meter (m 2 ). unit of volume is the cubic meter (m 3 ). The liter (1 cubic decimeter), although not an SI unit, is accepted for use with the SI and is commonly used when measuring fluid volume , but is also used when measuring gases and solids . Return to Top of Page Units of Length 10 millimeters (mm) = 1 centimeter (cm) 10 centimeters = 1 decimeter (dm) 10 centimeters = 100 millimeters 10 decimeters = 1 meter (m) 10 decimeters = 1000 millimeters 10 meters = 1 dekameter (dam) 10 dekameters = 1 hectometer (hm) 10 dekameters = 100 meters 10 hectometers = 1 kilometer (km) 10 hectometers = 1000 meters Return to Top of Page Resources for Students and Teachers Teachers: Top 10 Tips for Teaching the Metric System . (NIST) Credit: ©2020 U.S. Secretary of Commerce. All Rights Reserved. Resources for K-2 Not sure how to tell that scientific minded person in your life how you feel? Maybe our Superhero Valentine's Day cards will do the trick. Download these fun coloring pages for Meter Man and our SI Superheroes . The Metric Meal (option 2) focuses exclusively on length measurements and uses a multidisciplinary approach to build measurement skills. Practice measuring length with centimeters in the Squares and Rectangles activity (PBS). k-2 Calculate Focal Length (The Optical Society) – Use this hands-on activity to explore an important concept that’s used in STEAM tools like microscopes, telescopes, and cameras. K- Credit: ©2020 U.S. Secretary of Commerce. All Rights Reserved. Resources for Grade 3-5 League of SI Superheroes - Meter Man This comic book-style video animation series has been developed to help middle school students learn about the 7 SI base measurement units. SI Units Card Deck (SP 1297) - this activity offers a fun way to enhance understanding of the International System of Units. (NIST) Metric Estimation Game (SP 1336) - this fun, hands-on activity helps participants become familiar with SI measurements by practicing estimation skills. During this activity, participants will become familiar with using the metric system (International System of Units, SI) measurements on common, everyday items. Metric Ruler (SP 376) (NIST) - an educational tool designed to teach SI) length measurements. 3 What is a Nanometer ? (IEEE) – In this activity, develop an understanding of how small a nanometer really is. During the lesson, students will measure common classroom objects and convert the results to nanometers. 3 Length Column Game (Quintessential Instructional Archive) – Become familiar with equivalent metric length measurements. Draw a line to connect between like measurements. Look carefully, because some items do not have a match! 3 The Wright Way: Innovation Through Engineering (NASA) - This educational poster includes metric activities associated with the Wright Brothers' flight experiments and include constructing and testing a sled kite, analyzing the resulting data, and assembling a metric cube. The student worksheet includes the learning objectives and academic standards (Pre-K to 12th grades), the sled kite template, worksheet and metric cube. 3 SI Area (NIST) – Explore resources to become familiar with units used to measure area, including the hectare. SI Volume (NIST) – Explore resources to become familiar with units used to measure volume, including the liter. Credit: N. Hanacek/NIST Resources for Grade 6-8 Metric Estimation Game (SP 1336) - this fun, hands-on activity helps participants become familiar with SI measurements by practicing estimation skills. During this activity, participants will become familiar with using the metric system (International System of Units, SI) measurements on common, everyday items. SI Base Units Relationship Poster (SP 1247) (NIST) – a colorful poster illustrating the relationships of the International System of Units (SI) derived units with special names and symbols and the seven traditional base units. SI Units Card Deck (SP 1297 ) (NIST) – this activity offers a fun way to enhance understanding of the International System of Units, including the defining constants, base units, derived units with special names, and prefixes. Sea Floor Mapping (NOAA)- An educational resource on how scientists map the ocean floor using sonar and other technologies, with classroom materials included. Mountain in the Sea Exploration: Big Fleas Have Little Fleas! (NOAA) Grades 7-8 Life Science Lesson Plan - PDF Exploring the Inner Space of the Celebes Sea - Staying Up (NOAA) Grades 7-8 Life Science/Physical Science Lesson Plan - PDF Coral Reef Infographics Collection (NOAA) – A set of visually engaging posters and graphics that illustrate coral reef ecosystems, their importance, threats, and conservation efforts. Historic Meter Stick (Smithsonian National Museum of American History). This historic meter stick was used to teach length. One side is graduated in centimeters (cm) by alternate markings of black paint. One side is divided into decimeters, with alternate decimeters (dm) in plain wood or black paint. Examine Cell Size and Scale using an interactive graphic (University of Utah). How Do You Ensure That a Tape Measure is Accurate (NIST HDYMI Series) – Learn how a laser interferometer is used to precisely measure distances along a measuring tape. How Do You Measure the Depth of the Ocean (NIST HDYMI Series) – Scientists and researchers can use sonar, radar and satellite methods to measure ocean depth. The average ocean depth is 3.7 km, but the deepest part ever recorded is located in the Mariana Trench, at a depth of around 11 km. Garden Layout (University of California at Berkley, University of Nottingham) – Design, plan, and draw a garden to scale using a metric ruler. SI Area (NIST) – Explore resources to become familiar with units used to measure area, including the hectare. SI Volume (NIST) – Explore resources to become familiar with units used to measure volume, including the liter. Calculate Circumference, Area and Volume (NIST) – Become familiar with methods used to calculate the circumference, area, and volume of common objects. Credit: N. Hanacek/NIST Resources for Grade 9+ Metric Estimation Game (SP 1336) - this fun, hands-on activity helps participants become familiar with SI measurements by practicing estimation skills. During this activity, participants will become familiar with using the metric system (International System of Units, SI) measurements on common, everyday items. SI Units Card Deck (SP 1297) (NIST) – this activity offers a fun way to enhance understanding of the International System of Units, including the defining constants, base units, derived units with special names, and prefixes. Metric Ruler (SP 376) (NIST) - an educational tool designed to teach SI) length measurements. Meter (NIST) – Whether it’s the interminable distance to Grandma’s house, a span of cloth, the distance to the track and field race finish line, or the space between the unfathomably small transistors on a computer chip, length is one of the most familiar units of measurement. National Prototype Meter No. 27 (NIST)- An image of the U.S. National Prototype Meter, a platinum-iridium bar created in the late 1800s as one of 31 international standards. Deepwater Coral Expedition: Reefs Rigs, and Wrecks (NOAA) Grades 9-12 Physical Science Lesson Plan - PDF Using a Micrometer (University of Toronto)- This resource offers a detailed explanation of how to accurately measure small dimensions using a micrometer. Using the Vernier Calipers & Micrometer Screw Gauge (University of Cape Town, Department of Physics)- This detailed instructional guide explains how to read and use Vernier calipers and micrometer screw gauges for precise length measurements. Scale of Things Chart (U.S. Department of Energy)- This visual chart from the DOE's Office of Basic Energy Sciences illustrates the relative sizes of objects from the macroscopic to the atomic scale. Going the Distance on National Tape Measure Day (NIST) – Learn about the significance of tape measures, celebrated on National Tape Measure Day , July 14 th . SI Area (NIST) – Explore resources to become familiar with units used to measure area, including the hectare. SI Volume (NIST) – Explore resources to become familiar with units used to measure volume, including the liter. Return to Top of Page Videos How It’s Measured: Calibrating Tape Measures Inside a 60-meter-long underground tunnel, measurement scientists check the accuracy of tape measures. How to Read a Metric Ruler Bob and Sparky explain how to read a metric ruler. They look at meters, centimeters and millimeters. Also features Bob speaking fluent French. Return to Top of Page FAQ Credit: NIST How do I get a metric ruler? 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